Phytochemical and susceptibility of cocoa pod and seed extracts against mosquito larvae

Insecticides of synthetic origin can be replaced with plant extracts and their new bioactive constituents since they are more environmentally-friendly and have fewer adverse effects on non-target creatures. The aim of this study was to investigate the preliminary phytochemical and susceptibility of cocoa pod and seed extracts. The fruit of Theobroma cacao L. was collected from the biome of Olabisi Onabanjo University, Ago-Iwoye, Ogun state, Nigeria. Phytochemical screening was carried out to detect the presence of alkaloids, anthraquinone glycosides, cardiac glycosides, flavonoids,saponins, cardenolides, phenols and tannins using standard protocols. Four mosquito larvae were counted into six micro-well litre plates; n-hexane extracts of cocoa pod and seed at varying concentrations (100 mg/mL and 50 mg/mL) were added. The process was observed for 30 hours and the number of dead larvae was recorded. Mean values were compared between the processed and unprocessed insect samples using Independent Sample T-test while means were compared between the insect samples using two-way analysis of variance (ANOVA). The results of the phytochemical analysis showed the presence of alkaloids and saponins in the seed and pod extracts. Flavonoid, phlobatannins and steroid were present only in the pod extract. The results of the larvicidal bioassay for LC50 of the plant using the pod extract showed a significant difference at 10 hours of exposure with the positive control. At 20 hours and 30 hours, there was a significant difference between the seed extract and the positive control. The results of the larvicidal bioassay for LC100 of the plant showed a significant relationship between the pod and the positive control (kerosene) while the seed did not show any relationship until 30 hours of exposure.